A facile, time-saving fabrication method of high purity CsPbBr3 films for efficient solar cells

Abstract

All-brominated cesium lead bromide (CsPbBr3) perovskite solar cells (PSCs) have drawn growing attention owing to unprecedented stability in the family of perovskites. It usually employs a two-step method to prepare CsPbBr3 films owing to the low solubility of CsBr in the common solvents. The researchers have to provide enough Cs source through increasing the reaction time or repeat times of CsBr deposition so as to obtain the target CsPbBr3 films. The long preparation period and tedious process increase the time and economic cost, which may limit the practical application of CsPbBr3 solar cells. Herein, a facile method is proposed to prepare CsPbBr3 films, in which appropriate CsBr is pre-introduced into PbBr2 solutions in the first step, and CsBr/2-methoxyethanol solution (∼35 mg mL−1) is used as solution conversion medium in the second step. Benefitting from the pre-introduction of CsBr in the first step, a single phase of CsPbBr3 films with full coverage can be conversed for only once CsBr supplementation. After integrating the CsPbBr3 films into a solar cell, it delivers a power conversion efficiency (PCE) of 7.48% basing on the configuration of FTO/TiO2/CsPbBr3/Carbon. This work largely shortens the preparation time of CsPbBr3 films, which may provide a practical way for the large-scale production of CsPbBr3 based devices.